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package org.checkerframework.checker.lock;
import com.sun.source.tree.AnnotatedTypeTree;
import com.sun.source.tree.AnnotationTree;
import com.sun.source.tree.ArrayAccessTree;
import com.sun.source.tree.BinaryTree;
import com.sun.source.tree.CompoundAssignmentTree;
import com.sun.source.tree.ExpressionTree;
import com.sun.source.tree.IdentifierTree;
import com.sun.source.tree.MemberSelectTree;
import com.sun.source.tree.MethodInvocationTree;
import com.sun.source.tree.MethodTree;
import com.sun.source.tree.SynchronizedTree;
import com.sun.source.tree.Tree;
import com.sun.source.tree.VariableTree;
import com.sun.source.util.TreePath;
import java.lang.annotation.Annotation;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.concurrent.locks.Lock;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.annotation.processing.ProcessingEnvironment;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.Element;
import javax.lang.model.element.ElementKind;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.type.TypeKind;
import javax.lang.model.type.TypeMirror;
import org.checkerframework.checker.compilermsgs.qual.CompilerMessageKey;
import org.checkerframework.checker.lock.LockAnnotatedTypeFactory.SideEffectAnnotation;
import org.checkerframework.checker.lock.qual.EnsuresLockHeld;
import org.checkerframework.checker.lock.qual.EnsuresLockHeldIf;
import org.checkerframework.checker.lock.qual.GuardSatisfied;
import org.checkerframework.checker.lock.qual.GuardedBy;
import org.checkerframework.checker.lock.qual.GuardedByBottom;
import org.checkerframework.checker.lock.qual.GuardedByUnknown;
import org.checkerframework.checker.lock.qual.Holding;
import org.checkerframework.checker.lock.qual.LockHeld;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.common.basetype.BaseTypeChecker;
import org.checkerframework.common.basetype.BaseTypeVisitor;
import org.checkerframework.dataflow.expression.JavaExpression;
import org.checkerframework.dataflow.expression.Unknown;
import org.checkerframework.dataflow.qual.Deterministic;
import org.checkerframework.dataflow.qual.Pure;
import org.checkerframework.framework.flow.CFAbstractValue;
import org.checkerframework.framework.type.AnnotatedTypeFactory.ParameterizedExecutableType;
import org.checkerframework.framework.type.AnnotatedTypeMirror;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedDeclaredType;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedExecutableType;
import org.checkerframework.framework.type.QualifierHierarchy;
import org.checkerframework.framework.util.AnnotatedTypes;
import org.checkerframework.framework.util.JavaExpressionParseUtil.JavaExpressionParseException;
import org.checkerframework.framework.util.StringToJavaExpression;
import org.checkerframework.framework.util.dependenttypes.DependentTypesError;
import org.checkerframework.javacutil.AnnotationMirrorSet;
import org.checkerframework.javacutil.AnnotationUtils;
import org.checkerframework.javacutil.ElementUtils;
import org.checkerframework.javacutil.TreePathUtil;
import org.checkerframework.javacutil.TreeUtils;
import org.checkerframework.javacutil.TypeSystemError;
import org.checkerframework.javacutil.TypesUtils;
import org.plumelib.util.CollectionsPlume;
/**
* The LockVisitor enforces the special type-checking rules described in the Lock Checker manual
* chapter.
*
* @checker_framework.manual #lock-checker Lock Checker
*/
public class LockVisitor extends BaseTypeVisitor {
/** The class of GuardedBy */
private static final Class checkerGuardedByClass = GuardedBy.class;
/** The class of GuardSatisfied */
private static final Class checkerGuardSatisfiedClass =
GuardSatisfied.class;
/** A pattern for spotting self receiver */
protected static final Pattern SELF_RECEIVER_PATTERN = Pattern.compile("^(\\.(.*))?$");
/**
* Constructs a {@link LockVisitor}.
*
* @param checker the type checker to use
*/
public LockVisitor(BaseTypeChecker checker) {
super(checker);
}
@Override
public Void visitVariable(VariableTree tree, Void p) { // visit a variable declaration
// A user may not annotate a primitive type, a boxed primitive type or a String
// with any qualifier from the @GuardedBy hierarchy.
// They are immutable, so there is no need to guard them.
TypeMirror tm = TreeUtils.typeOf(tree);
if (TypesUtils.isBoxedPrimitive(tm) || TypesUtils.isPrimitive(tm) || TypesUtils.isString(tm)) {
AnnotatedTypeMirror atm = atypeFactory.getAnnotatedType(tree);
if (atm.hasExplicitAnnotationRelaxed(atypeFactory.GUARDSATISFIED)
|| atm.hasExplicitAnnotationRelaxed(atypeFactory.GUARDEDBY)
|| atm.hasExplicitAnnotation(atypeFactory.GUARDEDBYUNKNOWN)
|| atm.hasExplicitAnnotation(atypeFactory.GUARDEDBYBOTTOM)) {
checker.reportError(tree, "immutable.type.guardedby");
}
}
issueErrorIfMoreThanOneGuardedByAnnotationPresent(tree);
return super.visitVariable(tree, p);
}
/**
* Issues an error if two or more of the following annotations are present on a variable
* declaration.
*
*
* - {@code @org.checkerframework.checker.lock.qual.GuardedBy}
*
- {@code @net.jcip.annotations.GuardedBy}
*
- {@code @javax.annotation.concurrent.GuardedBy}
*
*
* @param variableTree the VariableTree for the variable declaration used to determine if
* multiple @GuardedBy annotations are present and to report the error
*/
private void issueErrorIfMoreThanOneGuardedByAnnotationPresent(VariableTree variableTree) {
int guardedByAnnotationCount = 0;
List annos =
TreeUtils.annotationsFromTypeAnnotationTrees(variableTree.getModifiers().getAnnotations());
for (AnnotationMirror anno : annos) {
if (atypeFactory.areSameByClass(anno, GuardedBy.class)
|| AnnotationUtils.areSameByName(anno, "net.jcip.annotations.GuardedBy")
|| AnnotationUtils.areSameByName(anno, "javax.annotation.concurrent.GuardedBy")) {
guardedByAnnotationCount++;
if (guardedByAnnotationCount > 1) {
checker.reportError(variableTree, "multiple.guardedby.annotations");
return;
}
}
}
}
@Override
public LockAnnotatedTypeFactory createTypeFactory() {
return new LockAnnotatedTypeFactory(checker);
}
/**
* Issues an error if a method (explicitly or implicitly) annotated with @MayReleaseLocks has a
* formal parameter or receiver (explicitly or implicitly) annotated with @GuardSatisfied. Also
* issues an error if a synchronized method has a @LockingFree, @SideEffectFree, or @Pure
* annotation.
*
* @param tree the MethodTree of the method definition to visit
*/
@Override
public Void visitMethod(MethodTree tree, Void p) {
ExecutableElement methodElement = TreeUtils.elementFromDeclaration(tree);
issueErrorIfMoreThanOneLockPreconditionMethodAnnotationPresent(methodElement, tree);
SideEffectAnnotation sea = atypeFactory.methodSideEffectAnnotation(methodElement, true);
if (sea == SideEffectAnnotation.MAYRELEASELOCKS) {
boolean issueGSwithMRLWarning = false;
VariableTree receiver = tree.getReceiverParameter();
if (receiver != null) {
if (atypeFactory
.getAnnotatedType(receiver)
.hasPrimaryAnnotation(checkerGuardSatisfiedClass)) {
issueGSwithMRLWarning = true;
}
}
if (!issueGSwithMRLWarning) { // Skip loop if we already decided to issue the warning.
for (VariableTree vt : tree.getParameters()) {
if (atypeFactory.getAnnotatedType(vt).hasPrimaryAnnotation(checkerGuardSatisfiedClass)) {
issueGSwithMRLWarning = true;
break;
}
}
}
if (issueGSwithMRLWarning) {
checker.reportError(tree, "guardsatisfied.with.mayreleaselocks");
}
}
// Issue an error if a non-constructor method definition has a return type of
// @GuardSatisfied without an index.
if (methodElement != null && methodElement.getKind() != ElementKind.CONSTRUCTOR) {
AnnotatedTypeMirror returnTypeATM = atypeFactory.getAnnotatedType(tree).getReturnType();
if (returnTypeATM != null && returnTypeATM.hasPrimaryAnnotation(GuardSatisfied.class)) {
int returnGuardSatisfiedIndex = atypeFactory.getGuardSatisfiedIndex(returnTypeATM);
if (returnGuardSatisfiedIndex == -1) {
checker.reportError(tree, "guardsatisfied.return.must.have.index");
}
}
}
if (!sea.isWeakerThan(SideEffectAnnotation.LOCKINGFREE)
&& methodElement.getModifiers().contains(Modifier.SYNCHRONIZED)) {
checker.reportError(tree, "lockingfree.synchronized.method", sea);
}
return super.visitMethod(tree, p);
}
/**
* Issues an error if two or more of the following annotations are present on a method.
*
*
* - {@code @Holding}
*
- {@code @net.jcip.annotations.GuardedBy}
*
- {@code @javax.annotation.concurrent.GuardedBy}
*
*
* @param methodElement the ExecutableElement for the method call referred to by {@code tree}
* @param treeForErrorReporting the MethodTree used to report the error
*/
private void issueErrorIfMoreThanOneLockPreconditionMethodAnnotationPresent(
ExecutableElement methodElement, MethodTree treeForErrorReporting) {
int lockPreconditionAnnotationCount = 0;
if (atypeFactory.getDeclAnnotation(methodElement, Holding.class) != null) {
lockPreconditionAnnotationCount++;
}
try {
if (atypeFactory.jcipGuardedBy != null
&& atypeFactory.getDeclAnnotation(methodElement, atypeFactory.jcipGuardedBy) != null) {
lockPreconditionAnnotationCount++;
}
if (lockPreconditionAnnotationCount < 2
&& atypeFactory.javaxGuardedBy != null
&& atypeFactory.getDeclAnnotation(methodElement, atypeFactory.javaxGuardedBy) != null) {
lockPreconditionAnnotationCount++;
}
} catch (Exception e) {
// Ignore exceptions from Class.forName
}
if (lockPreconditionAnnotationCount > 1) {
checker.reportError(treeForErrorReporting, "multiple.lock.precondition.annotations");
}
}
/**
* When visiting a method call, if the receiver formal parameter has type @GuardSatisfied and the
* receiver actual parameter has type @GuardedBy(...), this method verifies that the guard is
* satisfied, and it returns true, indicating that the receiver subtype check should be skipped.
* If the receiver actual parameter has type @GuardSatisfied, this method simply returns true
* without performing any other actions. The method returns false otherwise.
*
* @param methodInvocationTree the MethodInvocationTree of the method being called
* @param methodDefinitionReceiver the ATM of the formal receiver parameter of the method being
* called
* @param methodCallReceiver the ATM of the receiver argument of the method call
* @return whether the caller can skip the receiver subtype check
*/
@Override
protected boolean skipReceiverSubtypeCheck(
MethodInvocationTree methodInvocationTree,
AnnotatedTypeMirror methodDefinitionReceiver,
AnnotatedTypeMirror methodCallReceiver) {
AnnotationMirror primaryGb =
methodCallReceiver.getPrimaryAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN);
AnnotationMirror effectiveGb =
methodCallReceiver.getEffectiveAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN);
// If the receiver actual parameter has type @GuardSatisfied, skip the subtype check.
// Consider only a @GuardSatisfied primary annotation - hence use primaryGb instead of
// effectiveGb.
if (primaryGb != null && atypeFactory.areSameByClass(primaryGb, checkerGuardSatisfiedClass)) {
AnnotationMirror primaryGbOnMethodDefinition =
methodDefinitionReceiver.getPrimaryAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN);
if (primaryGbOnMethodDefinition != null
&& atypeFactory.areSameByClass(primaryGbOnMethodDefinition, checkerGuardSatisfiedClass)) {
return true;
}
}
if (atypeFactory.areSameByClass(effectiveGb, checkerGuardedByClass)) {
AnnotationMirrorSet annos = methodDefinitionReceiver.getPrimaryAnnotations();
AnnotationMirror guardSatisfied =
atypeFactory.getAnnotationByClass(annos, checkerGuardSatisfiedClass);
if (guardSatisfied != null) {
ExpressionTree receiverTree = TreeUtils.getReceiverTree(methodInvocationTree);
if (receiverTree == null) {
checkLockOfImplicitThis(methodInvocationTree, effectiveGb);
} else {
checkLock(receiverTree, effectiveGb);
}
return true;
}
}
return false;
}
@Override
protected AnnotationMirrorSet getExceptionParameterLowerBoundAnnotations() {
AnnotationMirrorSet tops = qualHierarchy.getTopAnnotations();
AnnotationMirrorSet annotationSet = new AnnotationMirrorSet();
for (AnnotationMirror anno : tops) {
if (AnnotationUtils.areSame(anno, atypeFactory.GUARDEDBYUNKNOWN)) {
annotationSet.add(atypeFactory.GUARDEDBY);
} else {
annotationSet.add(anno);
}
}
return annotationSet;
}
@Override
protected void checkConstructorResult(
AnnotatedExecutableType constructorType, ExecutableElement constructorElement) {
// Newly created objects are guarded by nothing, so allow @GuardedBy({}) on constructor
// results.
AnnotationMirror anno =
constructorType
.getReturnType()
.getPrimaryAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN);
if (AnnotationUtils.areSame(anno, atypeFactory.GUARDEDBYUNKNOWN)
|| AnnotationUtils.areSame(anno, atypeFactory.GUARDEDBYBOTTOM)) {
checker.reportWarning(constructorElement, "inconsistent.constructor.type", anno, null);
}
}
@Override
protected boolean commonAssignmentCheck(
AnnotatedTypeMirror varType,
AnnotatedTypeMirror valueType,
Tree valueTree,
@CompilerMessageKey String errorKey,
Object... extraArgs) {
// In cases where assigning a value with a @GuardedBy annotation to a variable with a
// @GuardSatisfied annotation is legal, this is our last chance to check that the
// appropriate locks are held before the information in the @GuardedBy annotation is lost in
// the assignment to the variable annotated with @GuardSatisfied. See the discussion of
// @GuardSatisfied in the "Type-checking rules" section of the Lock Checker manual chapter
// for more details.
boolean result = true;
if (varType.hasPrimaryAnnotation(GuardSatisfied.class)) {
if (valueType.hasPrimaryAnnotation(GuardedBy.class)) {
return checkLock(valueTree, valueType.getPrimaryAnnotation(GuardedBy.class));
} else if (valueType.hasPrimaryAnnotation(GuardSatisfied.class)) {
// TODO: Find a cleaner, non-abstraction-breaking way to know whether method actual
// parameters are being assigned to formal parameters.
if (!errorKey.equals("argument")) {
// If both @GuardSatisfied have no index, the assignment is not allowed because
// the LHS and RHS expressions may be guarded by different lock expressions.
// The assignment is allowed when matching a formal parameter to an actual
// parameter (see the if block above).
int varTypeGuardSatisfiedIndex = atypeFactory.getGuardSatisfiedIndex(varType);
int valueTypeGuardSatisfiedIndex = atypeFactory.getGuardSatisfiedIndex(valueType);
if (varTypeGuardSatisfiedIndex == -1 && valueTypeGuardSatisfiedIndex == -1) {
checker.reportError(
valueTree, "guardsatisfied.assignment.disallowed", varType, valueType);
result = false;
}
} else {
// The RHS can be @GuardSatisfied with a different index when matching method
// formal parameters to actual parameters.
// The actual matching is done in LockVisitor.visitMethodInvocation and a
// guardsatisfied.parameters.must.match error
// is issued if the parameters do not match exactly.
// Do nothing here, since there is no precondition to be checked on a
// @GuardSatisfied parameter.
// Note: this matching of a @GS(index) to a @GS(differentIndex) is *only*
// allowed when matching method formal parameters to actual parameters.
return true;
}
} else if (!atypeFactory.getTypeHierarchy().isSubtype(valueType, varType)) {
// Special case: replace the @GuardSatisfied primary annotation on the LHS with
// @GuardedBy({}) and see if it type checks.
AnnotatedTypeMirror varType2 = varType.deepCopy(); // TODO: Would shallowCopy be sufficient?
varType2.replaceAnnotation(atypeFactory.GUARDEDBY);
if (atypeFactory.getTypeHierarchy().isSubtype(valueType, varType2)) {
return true;
}
}
}
result =
super.commonAssignmentCheck(varType, valueType, valueTree, errorKey, extraArgs) && result;
return result;
}
@Override
public Void visitMemberSelect(MemberSelectTree tree, Void p) {
if (TreeUtils.isFieldAccess(tree)) {
AnnotatedTypeMirror atmOfReceiver = atypeFactory.getAnnotatedType(tree.getExpression());
// The atmOfReceiver for "void.class" is TypeKind.VOID, which isn't annotated so avoid
// it.
if (atmOfReceiver.getKind() != TypeKind.VOID) {
AnnotationMirror gb =
atmOfReceiver.getEffectiveAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN);
checkLock(tree.getExpression(), gb);
}
}
return super.visitMemberSelect(tree, p);
}
private void reportFailure(
@CompilerMessageKey String messageKey,
MethodTree overriderTree,
AnnotatedDeclaredType enclosingType,
AnnotatedExecutableType overridden,
AnnotatedDeclaredType overriddenType,
List overriderLocks,
List overriddenLocks) {
// Get the type of the overriding method.
AnnotatedExecutableType overrider = atypeFactory.getAnnotatedType(overriderTree);
if (overrider.getTypeVariables().isEmpty() && !overridden.getTypeVariables().isEmpty()) {
overridden = overridden.getErased();
}
String overriderMeth = overrider.toString();
String overriderTyp = enclosingType.getUnderlyingType().asElement().toString();
String overriddenMeth = overridden.toString();
String overriddenTyp = overriddenType.getUnderlyingType().asElement().toString();
if (overriderLocks == null || overriddenLocks == null) {
checker.reportError(
overriderTree, messageKey, overriderTyp, overriderMeth, overriddenTyp, overriddenMeth);
} else {
checker.reportError(
overriderTree,
messageKey,
overriderTyp,
overriderMeth,
overriddenTyp,
overriddenMeth,
overriderLocks,
overriddenLocks);
}
}
/**
* Ensures that subclass methods are annotated with a stronger or equally strong side effect
* annotation than the parent class method.
*/
@Override
protected boolean checkOverride(
MethodTree overriderTree,
AnnotatedDeclaredType enclosingType,
AnnotatedExecutableType overriddenMethodType,
AnnotatedDeclaredType overriddenType) {
boolean isValid = true;
SideEffectAnnotation seaOfOverriderMethod =
atypeFactory.methodSideEffectAnnotation(
TreeUtils.elementFromDeclaration(overriderTree), false);
SideEffectAnnotation seaOfOverriddenMethod =
atypeFactory.methodSideEffectAnnotation(overriddenMethodType.getElement(), false);
if (seaOfOverriderMethod.isWeakerThan(seaOfOverriddenMethod)) {
isValid = false;
reportFailure(
"override.sideeffect",
overriderTree,
enclosingType,
overriddenMethodType,
overriddenType,
null,
null);
}
return super.checkOverride(overriderTree, enclosingType, overriddenMethodType, overriddenType)
&& isValid;
}
@Override
public Void visitArrayAccess(ArrayAccessTree tree, Void p) {
AnnotatedTypeMirror atmOfReceiver = atypeFactory.getAnnotatedType(tree.getExpression());
AnnotationMirror gb =
atmOfReceiver.getEffectiveAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN);
checkLock(tree.getExpression(), gb);
return super.visitArrayAccess(tree, p);
}
/**
* Skips the call to super and returns true.
*
* {@code GuardedBy({})} is the default type on class declarations, which is a subtype of the
* top annotation {@code @GuardedByUnknown}. However, it is valid to declare an instance of a
* class with any annotation from the {@code @GuardedBy} hierarchy. Hence, this method returns
* true for annotations in the {@code @GuardedBy} hierarchy.
*
*
Also returns true for annotations in the {@code @LockPossiblyHeld} hierarchy since the
* default for that hierarchy is the top type and annotations from that hierarchy cannot be
* explicitly written in code.
*/
@Override
public boolean isValidUse(
AnnotatedDeclaredType declarationType, AnnotatedDeclaredType useType, Tree tree) {
return true;
}
/**
* When visiting a method invocation, issue an error if the side effect annotation on the called
* method causes the side effect guarantee of the enclosing method to be violated. For example, a
* method annotated with @ReleasesNoLocks may not call a method annotated with @MayReleaseLocks.
* Also check that matching @GuardSatisfied(index) on a method's formal receiver/parameters
* matches those in corresponding locations on the method call site.
*
* @param methodInvocationTree the MethodInvocationTree of the method call being visited
*/
@Override
public Void visitMethodInvocation(MethodInvocationTree methodInvocationTree, Void p) {
ExecutableElement methodElement = TreeUtils.elementFromUse(methodInvocationTree);
SideEffectAnnotation seaOfInvokedMethod =
atypeFactory.methodSideEffectAnnotation(methodElement, false);
MethodTree enclosingMethod =
TreePathUtil.enclosingMethod(atypeFactory.getPath(methodInvocationTree));
ExecutableElement enclosingMethodElement = null;
if (enclosingMethod != null) {
enclosingMethodElement = TreeUtils.elementFromDeclaration(enclosingMethod);
}
if (enclosingMethodElement != null) {
SideEffectAnnotation seaOfContainingMethod =
atypeFactory.methodSideEffectAnnotation(enclosingMethodElement, false);
if (seaOfInvokedMethod.isWeakerThan(seaOfContainingMethod)) {
checker.reportError(
methodInvocationTree,
"method.guarantee.violated",
seaOfContainingMethod.getNameOfSideEffectAnnotation(),
enclosingMethodElement.getSimpleName(),
methodElement.getSimpleName(),
seaOfInvokedMethod.getNameOfSideEffectAnnotation());
}
}
if (methodElement != null) {
// Handle releasing of explicit locks. Verify that the lock expression is effectively
// final.
ExpressionTree receiverTree = TreeUtils.getReceiverTree(methodInvocationTree);
ensureReceiverOfExplicitUnlockCallIsEffectivelyFinal(methodElement, receiverTree);
// Handle acquiring of explicit locks. Verify that the lock expression is effectively
// final.
// If the method causes expression "this" or "#1" to be locked, verify that those
// expressions are effectively final. TODO: generalize to any expression. This is
// currently designed only to support methods in ReentrantLock and
// ReentrantReadWriteLock (which use the "this" expression), as well as Thread.holdsLock
// (which uses the "#1" expression).
AnnotationMirror ensuresLockHeldAnno =
atypeFactory.getDeclAnnotation(methodElement, EnsuresLockHeld.class);
List expressions = new ArrayList<>();
if (ensuresLockHeldAnno != null) {
expressions.addAll(
AnnotationUtils.getElementValueArray(
ensuresLockHeldAnno, atypeFactory.ensuresLockHeldValueElement, String.class));
}
AnnotationMirror ensuresLockHeldIfAnno =
atypeFactory.getDeclAnnotation(methodElement, EnsuresLockHeldIf.class);
if (ensuresLockHeldIfAnno != null) {
expressions.addAll(
AnnotationUtils.getElementValueArray(
ensuresLockHeldIfAnno,
atypeFactory.ensuresLockHeldIfExpressionElement,
String.class));
}
for (String expr : expressions) {
if (expr.equals("this")) {
// receiverTree will be null for implicit this, or class name receivers. But
// they are also final. So nothing to be checked for them.
if (receiverTree != null) {
ensureExpressionIsEffectivelyFinal(receiverTree);
}
} else if (expr.equals("#1")) {
ExpressionTree firstParameter = methodInvocationTree.getArguments().get(0);
if (firstParameter != null) {
ensureExpressionIsEffectivelyFinal(firstParameter);
}
}
}
}
// Check that matching @GuardSatisfied(index) on a method's formal receiver/parameters
// matches those in corresponding locations on the method call site.
ParameterizedExecutableType mType = atypeFactory.methodFromUse(methodInvocationTree);
AnnotatedExecutableType invokedMethod = mType.executableType;
List paramTypes =
AnnotatedTypes.adaptParameters(
atypeFactory, invokedMethod, methodInvocationTree.getArguments());
// Index on @GuardSatisfied at each location. -1 when no @GuardSatisfied annotation was
// present.
// Note that @GuardSatisfied with no index is normally represented as having index -1.
// We would like to ignore a @GuardSatisfied with no index for these purposes, so if it is
// encountered we leave its index as -1.
// The first element of the array is reserved for the receiver.
int guardSatisfiedIndex[] =
new int[paramTypes.size() + 1]; // + 1 for the receiver parameter type
// Retrieve receiver types from method definition and method call
guardSatisfiedIndex[0] = -1;
AnnotatedTypeMirror methodDefinitionReceiver = null;
AnnotatedTypeMirror methodCallReceiver = null;
ExecutableElement invokedMethodElement = invokedMethod.getElement();
if (!ElementUtils.isStatic(invokedMethodElement)
&& invokedMethod.getElement().getKind() != ElementKind.CONSTRUCTOR) {
methodDefinitionReceiver = invokedMethod.getReceiverType();
if (methodDefinitionReceiver != null
&& methodDefinitionReceiver.hasPrimaryAnnotation(checkerGuardSatisfiedClass)) {
guardSatisfiedIndex[0] = atypeFactory.getGuardSatisfiedIndex(methodDefinitionReceiver);
methodCallReceiver = atypeFactory.getReceiverType(methodInvocationTree);
}
}
// Retrieve formal parameter types from the method definition.
for (int i = 0; i < paramTypes.size(); i++) {
guardSatisfiedIndex[i + 1] = -1;
AnnotatedTypeMirror paramType = paramTypes.get(i);
if (paramType.hasPrimaryAnnotation(checkerGuardSatisfiedClass)) {
guardSatisfiedIndex[i + 1] = atypeFactory.getGuardSatisfiedIndex(paramType);
}
}
// Combine all of the actual parameters into one list of AnnotationMirrors.
ArrayList passedArgTypes = new ArrayList<>(guardSatisfiedIndex.length);
passedArgTypes.add(methodCallReceiver);
for (ExpressionTree argTree : methodInvocationTree.getArguments()) {
passedArgTypes.add(atypeFactory.getAnnotatedType(argTree));
}
ArrayList passedArgAnnotations = new ArrayList<>(guardSatisfiedIndex.length);
for (AnnotatedTypeMirror atm : passedArgTypes) {
passedArgAnnotations.add(
atm == null ? null : atm.getPrimaryAnnotationInHierarchy(atypeFactory.GUARDEDBYUNKNOWN));
}
// Perform the validity check and issue an error if not valid.
for (int i = 0; i < guardSatisfiedIndex.length; i++) {
if (guardSatisfiedIndex[i] != -1) {
for (int j = i + 1; j < guardSatisfiedIndex.length; j++) {
if (guardSatisfiedIndex[i] == guardSatisfiedIndex[j]) {
// The @GuardedBy/@GuardSatisfied/@GuardedByUnknown/@GuardedByBottom
// annotations must be identical on the corresponding actual parameters.
AnnotationMirror arg1Anno = passedArgAnnotations.get(i);
AnnotationMirror arg2Anno = passedArgAnnotations.get(j);
if (arg1Anno != null && arg2Anno != null) {
boolean bothAreGSwithNoIndex = false;
if (atypeFactory.areSameByClass(arg1Anno, checkerGuardSatisfiedClass)
&& atypeFactory.areSameByClass(arg2Anno, checkerGuardSatisfiedClass)) {
if (atypeFactory.getGuardSatisfiedIndex(arg1Anno) == -1
&& atypeFactory.getGuardSatisfiedIndex(arg2Anno) == -1) {
// Generally speaking, two @GuardSatisfied annotations with no
// index are incomparable.
// TODO: If they come from the same variable, they are
// comparable. Fix and add a test case.
bothAreGSwithNoIndex = true;
}
}
TypeMirror arg1TM = passedArgTypes.get(i).getUnderlyingType();
TypeMirror arg2TM = passedArgTypes.get(j).getUnderlyingType();
if (bothAreGSwithNoIndex
|| !(qualHierarchy.isSubtypeShallow(arg1Anno, arg1TM, arg2Anno, arg2TM)
|| qualHierarchy.isSubtypeShallow(arg2Anno, arg2TM, arg1Anno, arg1TM))) {
String formalParam1;
if (i == 0) {
formalParam1 = "The receiver type";
} else {
formalParam1 = "Parameter #" + i; // i, not i-1, so the index is 1-based
}
String formalParam2 = "parameter #" + j; // j, not j-1, so the index is 1-based
checker.reportError(
methodInvocationTree,
"guardsatisfied.parameters.must.match",
formalParam1,
formalParam2,
invokedMethod.toString(),
guardSatisfiedIndex[i],
arg1Anno,
arg2Anno);
}
}
}
}
}
}
return super.visitMethodInvocation(methodInvocationTree, p);
}
/**
* Issues an error if the receiver of an unlock() call is not effectively final.
*
* @param methodElement the ExecutableElement for a method call to unlock()
* @param lockExpression the receiver tree for the method call to unlock(). Can be null.
*/
private void ensureReceiverOfExplicitUnlockCallIsEffectivelyFinal(
ExecutableElement methodElement, @Nullable ExpressionTree lockExpression) {
if (lockExpression == null) {
// Implicit this, or class name receivers, are null. But they are also final. So nothing
// to be checked for them.
return;
}
if (!methodElement.getSimpleName().contentEquals("unlock")) {
return;
}
TypeMirror lockExpressionType = TreeUtils.typeOf(lockExpression);
ProcessingEnvironment processingEnvironment = checker.getProcessingEnvironment();
javax.lang.model.util.Types types = processingEnvironment.getTypeUtils();
// TODO: make a type declaration annotation for this rather than looking for the
// Lock.unlock() method explicitly.
TypeMirror lockInterfaceTypeMirror =
TypesUtils.typeFromClass(Lock.class, types, processingEnvironment.getElementUtils());
if (types.isSubtype(types.erasure(lockExpressionType), lockInterfaceTypeMirror)) {
ensureExpressionIsEffectivelyFinal(lockExpression);
}
}
/**
* When visiting a synchronized block, issue an error if the expression has a type that implements
* the java.util.concurrent.locks.Lock interface. This prevents explicit locks from being
* accidentally used as built-in (monitor) locks. This is important because the Lock Checker does
* not have a mechanism to separately keep track of the explicit lock and the monitor lock of an
* expression that implements the Lock interface (i.e. there is a @LockHeld annotation used in
* dataflow, but there are not distinct @MonitorLockHeld and @ExplicitLockHeld annotations). It is
* assumed that both kinds of locks will never be held for any expression that implements Lock.
*
* Additionally, a synchronized block may not be present in a method that has a @LockingFree
* guarantee or stronger. An error is issued in this case.
*
* @param tree the SynchronizedTree for the synchronized block being visited
*/
@Override
public Void visitSynchronized(SynchronizedTree tree, Void p) {
ProcessingEnvironment processingEnvironment = checker.getProcessingEnvironment();
javax.lang.model.util.Types types = processingEnvironment.getTypeUtils();
// TODO: make a type declaration annotation for this rather than looking for Lock.class
// explicitly.
TypeMirror lockInterfaceTypeMirror =
TypesUtils.typeFromClass(Lock.class, types, processingEnvironment.getElementUtils());
ExpressionTree synchronizedExpression = tree.getExpression();
ensureExpressionIsEffectivelyFinal(synchronizedExpression);
TypeMirror expressionType =
types.erasure(atypeFactory.getAnnotatedType(synchronizedExpression).getUnderlyingType());
if (types.isSubtype(expressionType, lockInterfaceTypeMirror)) {
checker.reportError(tree, "explicit.lock.synchronized");
}
MethodTree enclosingMethod = TreePathUtil.enclosingMethod(atypeFactory.getPath(tree));
ExecutableElement methodElement = null;
if (enclosingMethod != null) {
methodElement = TreeUtils.elementFromDeclaration(enclosingMethod);
SideEffectAnnotation seaOfContainingMethod =
atypeFactory.methodSideEffectAnnotation(methodElement, false);
if (!seaOfContainingMethod.isWeakerThan(SideEffectAnnotation.LOCKINGFREE)) {
checker.reportError(
tree, "synchronized.block.in.lockingfree.method", seaOfContainingMethod);
}
}
return super.visitSynchronized(tree, p);
}
/**
* Ensures that each variable accessed in an expression is final or effectively final and that
* each called method in the expression is @Deterministic. Issues an error otherwise. Recursively
* performs this check on method arguments. Only intended to be used on the expression of a
* synchronized block.
*
*
Example: given the expression var1.field1.method1(var2.method2()).field2, var1, var2, field1
* and field2 are enforced to be final or effectively final, and method1 and method2 are enforced
* to be @Deterministic.
*
* @param lockExpressionTree the expression tree of a synchronized block
* @return true if the check succeeds, false if an error message was issued
*/
private boolean ensureExpressionIsEffectivelyFinal(ExpressionTree lockExpressionTree) {
// This functionality could be implemented using a visitor instead, however with this
// design, it is easier to be certain that an error will always be issued if a tree kind is
// not recognized.
// Only the most common tree kinds for synchronized expressions are supported.
// Traverse the expression using 'tree', as 'lockExpressionTree' is used for error
// reporting.
ExpressionTree tree = lockExpressionTree;
boolean result = true;
while (true) {
tree = TreeUtils.withoutParens(tree);
switch (tree.getKind()) {
case MEMBER_SELECT:
if (!isTreeSymbolEffectivelyFinalOrUnmodifiable(tree)) {
checker.reportError(tree, "lock.expression.not.final", lockExpressionTree);
return false;
}
tree = ((MemberSelectTree) tree).getExpression();
break;
case IDENTIFIER:
if (!isTreeSymbolEffectivelyFinalOrUnmodifiable(tree)) {
checker.reportError(tree, "lock.expression.not.final", lockExpressionTree);
return false;
}
return result;
case METHOD_INVOCATION:
Element elem = TreeUtils.elementFromUse(tree);
if (atypeFactory.getDeclAnnotationNoAliases(elem, Deterministic.class) == null
&& atypeFactory.getDeclAnnotationNoAliases(elem, Pure.class) == null) {
checker.reportError(tree, "lock.expression.not.final", lockExpressionTree);
return false;
}
MethodInvocationTree methodInvocationTree = (MethodInvocationTree) tree;
for (ExpressionTree argTree : methodInvocationTree.getArguments()) {
result = ensureExpressionIsEffectivelyFinal(argTree) && result;
}
tree = methodInvocationTree.getMethodSelect();
break;
default:
checker.reportError(tree, "lock.expression.possibly.not.final", lockExpressionTree);
return false;
}
}
}
/**
* Issues an error if the given expression is not effectively final. Returns true if the
* expression is effectively final, false if an error was issued.
*
* @param lockExpr an expression that might be effectively final
* @param expressionForErrorReporting how to print the expression in an error message
* @param treeForErrorReporting where to report the error
* @return true if the expression is effectively final, false if an error was issued
*/
private boolean ensureExpressionIsEffectivelyFinal(
JavaExpression lockExpr, String expressionForErrorReporting, Tree treeForErrorReporting) {
boolean result = atypeFactory.isExpressionEffectivelyFinal(lockExpr);
if (!result) {
checker.reportError(
treeForErrorReporting, "lock.expression.not.final", expressionForErrorReporting);
}
return result;
}
@Override
public Void visitAnnotation(AnnotationTree tree, Void p) {
ArrayList annotationTreeList = new ArrayList<>(1);
annotationTreeList.add(tree);
List amList =
TreeUtils.annotationsFromTypeAnnotationTrees(annotationTreeList);
if (amList != null) {
for (AnnotationMirror annotationMirror : amList) {
if (atypeFactory.areSameByClass(annotationMirror, checkerGuardSatisfiedClass)) {
issueErrorIfGuardSatisfiedAnnotationInUnsupportedLocation(tree);
}
}
}
return super.visitAnnotation(tree, p);
}
/**
* Issues an error if a GuardSatisfied annotation is found in a location other than a method
* return type or parameter (including the receiver).
*
* @param annotationTree an AnnotationTree used for error reporting and to help determine that an
* array parameter has no GuardSatisfied annotations except on the array type
*/
// TODO: Remove this method once @TargetLocations are enforced (i.e. once
// issue https://github.com/typetools/checker-framework/issues/1919 is closed).
private void issueErrorIfGuardSatisfiedAnnotationInUnsupportedLocation(
AnnotationTree annotationTree) {
TreePath currentPath = getCurrentPath();
TreePath path = getPathForLocalVariableRetrieval(currentPath);
if (path != null) {
Tree tree = path.getLeaf();
Tree.Kind kind = tree.getKind();
if (kind == Tree.Kind.METHOD) {
// The @GuardSatisfied annotation is on the return type.
return;
} else if (kind == Tree.Kind.VARIABLE) {
VariableTree varTree = (VariableTree) tree;
Tree varTypeTree = varTree.getType();
if (varTypeTree != null) {
TreePath parentPath = path.getParentPath();
if (parentPath != null && parentPath.getLeaf().getKind() == Tree.Kind.METHOD) {
Tree.Kind varTypeTreeKind = varTypeTree.getKind();
if (varTypeTreeKind == Tree.Kind.ANNOTATED_TYPE) {
AnnotatedTypeTree annotatedTypeTree = (AnnotatedTypeTree) varTypeTree;
if (annotatedTypeTree.getUnderlyingType().getKind() != Tree.Kind.ARRAY_TYPE
|| annotatedTypeTree.getAnnotations().contains(annotationTree)) {
// Method parameter
return;
}
} else if (varTypeTreeKind != Tree.Kind.ARRAY_TYPE) {
// Method parameter or receiver
return;
}
}
}
}
}
checker.reportError(annotationTree, "guardsatisfied.location.disallowed");
}
/**
* The JavaExpression parser requires a path for retrieving the scope that will be used to resolve
* local variables. One would expect that simply providing the path to an AnnotationTree would
* work, since the compiler (as called by the org.checkerframework.javacutil.Resolver class) could
* walk up the path from the AnnotationTree to determine the scope. Unfortunately this is not how
* the compiler works. One must provide the path at the right level (not so deep that it results
* in a symbol not being found, but not so high up that it is out of the scope at hand). This is a
* problem when trying to retrieve local variables, since one could silently miss a local variable
* in scope and accidentally retrieve a field with the same name. This method returns the correct
* path for this purpose, given a path to an AnnotationTree.
*
* Note: this is definitely necessary for local variable retrieval. It has not been tested
* whether this is strictly necessary for fields or other identifiers.
*
*
Only call this method from visitAnnotation.
*
* @param path the TreePath whose leaf is an AnnotationTree
* @return a TreePath that can be passed to methods in the Resolver class to locate local
* variables
*/
private @Nullable TreePath getPathForLocalVariableRetrieval(TreePath path) {
assert path.getLeaf() instanceof AnnotationTree;
// TODO: handle annotations in trees of kind NEW_CLASS (and add test coverage for this
// scenario).
// Currently an annotation in such a tree, such as "new @GuardedBy("foo") Object()",
// results in a "constructor.invocation" error. This must be fixed first.
path = path.getParentPath();
if (path == null) {
return null;
}
// A MODIFIERS tree for a VARIABLE or METHOD parent tree would be available at this level,
// but it is not directly handled. Instead, its parent tree (one level higher) is handled.
// Other tree kinds are also handled one level higher.
path = path.getParentPath();
if (path == null) {
return null;
}
Tree tree = path.getLeaf();
Tree.Kind kind = tree.getKind();
switch (kind) {
case ARRAY_TYPE:
case VARIABLE:
case TYPE_CAST:
case INSTANCE_OF:
case METHOD:
case NEW_ARRAY:
case TYPE_PARAMETER:
// TODO: visitAnnotation does not currently visit annotations on wildcard bounds.
// Address this for the Lock Checker somehow and enable these, as well as the
// corresponding test cases in ChapterExamples.java
// case EXTENDS_WILDCARD:
// case SUPER_WILDCARD:
return path;
default:
return null;
}
}
/**
* Returns true if the symbol for the given tree is final or effectively final. Package, class and
* method symbols are unmodifiable and therefore considered final.
*
* @param tree the tree to test
* @return true if the symbol for the given tree is final or effectively final
*/
private boolean isTreeSymbolEffectivelyFinalOrUnmodifiable(Tree tree) {
Element elem = TreeUtils.elementFromTree(tree);
ElementKind ek = elem.getKind();
return ek == ElementKind.PACKAGE
|| ek == ElementKind.CLASS
|| ek == ElementKind.METHOD
|| ElementUtils.isEffectivelyFinal(elem);
}
@Override
@SuppressWarnings("interning:not.interned") // AST node comparison
public Void visitIdentifier(IdentifierTree tree, Void p) {
// If the identifier is a field accessed via an implicit this, then check the lock of this.
// (All other field accesses are checked in visitMemberSelect.)
if (TreeUtils.isFieldAccess(tree)) {
Tree parent = getCurrentPath().getParentPath().getLeaf();
// If the parent is not a member select, or if it is and the field is the expression,
// then the field is accessed via an implicit this.
if ((parent.getKind() != Tree.Kind.MEMBER_SELECT
|| ((MemberSelectTree) parent).getExpression() == tree)
&& !ElementUtils.isStatic(TreeUtils.elementFromUse(tree))) {
AnnotationMirror guardedBy =
atypeFactory.getSelfType(tree).getPrimaryAnnotationInHierarchy(atypeFactory.GUARDEDBY);
checkLockOfImplicitThis(tree, guardedBy);
}
}
return super.visitIdentifier(tree, p);
}
@Override
public Void visitBinary(BinaryTree binaryTree, Void p) {
if (TreeUtils.isStringConcatenation(binaryTree)) {
ExpressionTree leftTree = binaryTree.getLeftOperand();
ExpressionTree rightTree = binaryTree.getRightOperand();
boolean lhsIsString = TypesUtils.isString(TreeUtils.typeOf(leftTree));
boolean rhsIsString = TypesUtils.isString(TreeUtils.typeOf(rightTree));
if (!lhsIsString) {
checkPreconditionsForImplicitToStringCall(leftTree);
} else if (!rhsIsString) {
checkPreconditionsForImplicitToStringCall(rightTree);
}
}
return super.visitBinary(binaryTree, p);
}
@Override
public Void visitCompoundAssignment(CompoundAssignmentTree tree, Void p) {
if (TreeUtils.isStringCompoundConcatenation(tree)) {
ExpressionTree rightTree = tree.getExpression();
if (!TypesUtils.isString(TreeUtils.typeOf(rightTree))) {
checkPreconditionsForImplicitToStringCall(rightTree);
}
}
return super.visitCompoundAssignment(tree, p);
}
/**
* Checks precondition for {@code tree} that is known to be the receiver of an implicit toString()
* call. The receiver of toString() is defined in the annotated JDK to be @GuardSatisfied.
* Therefore if the expression is guarded by a set of locks, the locks must be held prior to this
* implicit call to toString().
*
*
Only call this method from visitBinary and visitCompoundAssignment.
*
* @param tree the Tree corresponding to the expression that is known to be the receiver of an
* implicit toString() call
*/
// TODO: If and when the de-sugared .toString() tree is accessible from BaseTypeVisitor,
// the toString() method call should be visited instead of doing this. This would result
// in "contracts.precondition" errors being issued instead of
// "contracts.precondition.field", so it would be clear that
// the error refers to an implicit method call, not a dereference (field access).
private void checkPreconditionsForImplicitToStringCall(ExpressionTree tree) {
AnnotationMirror gbAnno =
atypeFactory
.getAnnotatedType(tree)
.getEffectiveAnnotationInHierarchy(atypeFactory.GUARDEDBY);
checkLock(tree, gbAnno);
}
private void checkLockOfImplicitThis(Tree tree, AnnotationMirror gbAnno) {
checkLockOfThisOrTree(tree, true, gbAnno);
}
/**
* Checks the lock of the given tree.
*
* @param tree a tree whose lock to check
* @param gbAnno a {@code @GuardedBy} annotation
* @return true if the check succeeds, false if an error message was issued
*/
private boolean checkLock(Tree tree, AnnotationMirror gbAnno) {
return checkLockOfThisOrTree(tree, false, gbAnno);
}
/**
* Helper method that checks the lock of either the implicit {@code this} or the given tree.
*
* @param tree a tree whose lock to check
* @param implicitThis true if checking the lock of the implicit {@code this}
* @param gbAnno a {@code @GuardedBy} annotation
* @return true if the check succeeds, false if an error message was issued
*/
private boolean checkLockOfThisOrTree(Tree tree, boolean implicitThis, AnnotationMirror gbAnno) {
if (gbAnno == null) {
throw new TypeSystemError("LockVisitor.checkLock: gbAnno cannot be null");
}
if (atypeFactory.areSameByClass(gbAnno, GuardedByUnknown.class)
|| atypeFactory.areSameByClass(gbAnno, GuardedByBottom.class)) {
checker.reportError(tree, "lock.not.held", "unknown lock " + gbAnno);
return false;
} else if (atypeFactory.areSameByClass(gbAnno, GuardSatisfied.class)) {
return true;
}
List expressions = getLockExpressions(implicitThis, gbAnno, tree);
if (expressions.isEmpty()) {
return true;
}
boolean result = true;
LockStore store = atypeFactory.getStoreBefore(tree);
for (LockExpression expression : expressions) {
if (expression.error != null) {
checker.reportError(tree, "expression.unparsable", expression.error.toString());
result = false;
} else if (expression.lockExpression == null) {
checker.reportError(tree, "expression.unparsable", expression.expressionString);
result = false;
} else if (!isLockHeld(expression.lockExpression, store)) {
checker.reportError(tree, "lock.not.held", expression.lockExpression.toString());
result = false;
}
if (expression.error != null && expression.lockExpression != null) {
result =
ensureExpressionIsEffectivelyFinal(
expression.lockExpression, expression.expressionString, tree)
&& result;
}
}
return result;
}
private boolean isLockHeld(JavaExpression lockExpr, LockStore store) {
if (store == null) {
return false;
}
CFAbstractValue value = store.getValue(lockExpr);
if (value == null) {
return false;
}
AnnotationMirrorSet annos = value.getAnnotations();
QualifierHierarchy hierarchy = qualHierarchy;
AnnotationMirror lockAnno =
hierarchy.findAnnotationInSameHierarchy(annos, atypeFactory.LOCKHELD);
return lockAnno != null && atypeFactory.areSameByClass(lockAnno, LockHeld.class);
}
private List getLockExpressions(
boolean implicitThis, AnnotationMirror gbAnno, Tree tree) {
List expressions =
AnnotationUtils.getElementValueArray(
gbAnno, atypeFactory.guardedByValueElement, String.class, Collections.emptyList());
if (expressions.isEmpty()) {
return Collections.emptyList();
}
TreePath currentPath = getCurrentPath();
TypeMirror enclosingType = TreeUtils.typeOf(TreePathUtil.enclosingClass(currentPath));
JavaExpression pseudoReceiver = JavaExpression.getPseudoReceiver(currentPath, enclosingType);
JavaExpression self;
if (implicitThis) {
self = pseudoReceiver;
} else if (TreeUtils.isExpressionTree(tree)) {
self = JavaExpression.fromTree((ExpressionTree) tree);
} else {
self = new Unknown(tree);
}
return CollectionsPlume.mapList(
expression -> parseExpressionString(expression, currentPath, self), expressions);
}
/**
* Parse a Java expression.
*
* @param expression the Java expression
* @param path the path to the expression
* @param itself the self expression
* @return the parsed expression
*/
private LockExpression parseExpressionString(
String expression, TreePath path, JavaExpression itself) {
LockExpression lockExpression = new LockExpression(expression);
if (DependentTypesError.isExpressionError(expression)) {
lockExpression.error = DependentTypesError.unparse(expression);
return lockExpression;
}
Matcher selfReceiverMatcher = SELF_RECEIVER_PATTERN.matcher(expression);
try {
if (selfReceiverMatcher.matches()) {
String remainingExpression = selfReceiverMatcher.group(2);
if (remainingExpression == null || remainingExpression.isEmpty()) {
lockExpression.lockExpression = itself;
if (!atypeFactory.isExpressionEffectivelyFinal(lockExpression.lockExpression)) {
checker.reportError(
path.getLeaf(), "lock.expression.not.final", lockExpression.lockExpression);
}
return lockExpression;
} else {
lockExpression.lockExpression =
StringToJavaExpression.atPath(
itself.toString() + "." + remainingExpression, path, checker);
if (!atypeFactory.isExpressionEffectivelyFinal(lockExpression.lockExpression)) {
checker.reportError(
path.getLeaf(), "lock.expression.not.final", lockExpression.lockExpression);
}
return lockExpression;
}
} else {
lockExpression.lockExpression = StringToJavaExpression.atPath(expression, path, checker);
return lockExpression;
}
} catch (JavaExpressionParseException ex) {
lockExpression.error = new DependentTypesError(expression, ex);
return lockExpression;
}
}
private static class LockExpression {
final String expressionString;
JavaExpression lockExpression = null;
DependentTypesError error = null;
LockExpression(String expression) {
this.expressionString = expression;
}
}
}